Applying the electronic nose in the environment : requirements for the instrument

Applying the electronic nose to monitor environmental odours is not straightforward. The instrument must be adapted to the final objectives. It has to pass different steps : suitable sensor selection, right choice of the target when supervised methods are used for data processing, choosing an odour-related dependant variable when using regressions, coping with the variability of environmental odour, taking the sensor drift into account, working only in concentrations above the limit of detection of the sensors, working with a mobile instrument in the field and coping with the ambient parameters.